Heart contractions cause periodic wavy buckling of microtubles.
When compressive forces push on a microtubule in a cell, such as when a growing polymer butts up against the cell edge, the fiber bends in multiple short wavelength curves like a snake. By contrast, when the end of an isolated microtubule is pushed with even small forces, the fiber compresses and bends in a single large arch. The minor forces necessary to bend isolated microtubules call into question the importance of the fibers in determining cell shape and strength.
Brangwynne et al. found that if they pressed on the end of a microtubule inside a cell with a microneedle, short wavelength bending occurred. Moreover, contraction of the actin–myosin cytoskeleton induced such buckling in rhythmically contracting...
